Oldsmaniac

Ok, maybe I should have read the can but bought 3, 1lb cans of refrigerant to convert my 92 Custom Cruiser. The compressor is shot so figured I may as well. I buy 3 cans of 134a at about 15 bucks a pop. One was marked initial charge with oil to protect new compressors on startup....great just what I need! It has been a hot sunny weekend and the 3 cans were just tossed in the back of the Olds wagon. Today I get in and smell something unusual but not overpowering and sorta familiar. After work I open up the rear glass and move one of the cans and its empty. I look at the bottom and there is a half moon split. I grab the other 2 and they are exactly the same.... so I lost about 50 bucks worth of refrigerant because of my stupidity!

stevengerard

wow, 134 $15 seemed like yesterday R12 was less than that

MDchanic

Yeah, 134's gotten crazy this year.

I'd better check the ones I keep in my own trunk now.

- Eric

Funkwagon455

The compressor locked up on my '92 Cruiser last month, Thank God that I had the sense to buy two 30 pound bottles of R12 a couple of years ago while I was down in Santa Cruz Bolivia! I think it was $220 a bottle, my memory is a little hazy from all of the Cachasa and Tres Estrellas. I keep my bottles climate controlled just in case. R12 operates at a lower pressure increasing component longevity and does not stop cooling when you are stuck in traffic or sitting still, it is still available and sometimes cheaper on C/L. Enjoy your CCruiser, they are one of the best kept secrets.

jensenracing77

and will be going higher again by next year. we go through thousands of lbs of 404A at work and was told it was getting ready to go up last winter. we pre bought 50,000lbs of it and wish we got more.

refrigerants are a sponge for heat. that is why they have that relief in the bottom of the can. if not it would have exploded and not just blew out the relief.

jensenracing77

that was a steal on R12 even last summer. we got a 50lb bottle last year and it was a little over $4000.

Oldsmaniac

This is my second 92 Cruiser. 1st one was light blue with cloth interior. Body rot started, engine and trans got tired. Found this maroon one with leather and very low miles for cheap.... They are the smoothest riding and most dependable vehicles I have ever owned, both 5.7's I do have about 20 lbs of R-12 but figured I would do the 134 conversion.

Lady72nRob71

Bummer...
It musta gotten quite hot for those cans to split like that!
The higher the temperature, the higher the pressure in the cans. Nature of the chemical and thats what make it work in refrigerant systems.
That is one of the reason why the bottom of my freezer is stocked with cans o' R12 - to keep the pressure lower and moisture away...

R134 is fixing to go the route of R12 as a newer "safer" but "slightly flammable" R is brought about. However, the free sale of 134 should not get banned like R12 did.
At least this is what I had heard.
Stock up on 134 if you find it at a good price - I need to!

jag1886

I just called my air guy yesterday and talked to him about the R134 in my 65 (someone converted it but didn't do all the stuff you are suppose to do) he told me he would change it back to R12, it appears that there is a lot of R12 around yet (he's says he does almost as much R12 stuff as R134) he told me that R12 is only illegal to produce not to use and that the 2 cost almost the same amount these days and besides the air will work better. He told me if you don't change out the hoses on an R12 car the R134 will just leak out through the hoses anyway.
I'm only bringing this up because maybe you should just take your car in and have someone evacuate and refill it with R12.

jensenracing77

R12 is way higher than 134A. if he can do them for about the same price he is charging to much for 134A or not enough for R12. 134 won't leak out of R12 hoses if the hoses are good. if they arn't good the R12 will also leak out. now if they are weak but not leaking with R12 then they could go bad because of the higher pressure of 134A. i have converted dozens of cars and never had a problem. the first one i did was a 91 S10 around 11 years ago. it still works on the same charge to this day. i have never converted an older car (pre 77). but yes, R12 will work much better than 134A in an R12 system.

the funny thing to this stuff is the EPA, they want "environmentally safe" refrigerant and also want better miles per gallon in our cars. every time they go to a safer refrigerant they operate on higher pressure and will use more gas or energy to operate

jag1886

This is good to know. My air guy says that R12 has been the same price for a long time and R134 goes up ever time he gets a new shipment he also mentioned the higher operating pressures when using R134, he also mentioned the leaking hose problem is caused by the molicules of the R134 are much smaller and that's why it leaks out through the hose (it may be that old car hoses are built out of a different kind of rubber than new car hoses) or it could be like putting larger molecule Nitrogen in your tires and they don't leak down.
Anyway I'm converting back to what it's suppose to have in it for as long as I can get it.

MDchanic

Interesting discussion on this point here.

As far as the nitrogen in tires, I call BS.

- Eric

jensenracing77

i know we are drifting away from the OP but the original reason for nitrogen in tires was because heat don't affect the pressure of nitrogen. if you have a properly inflated tire in the summer, it will be lower in the winter if you don't adjust for it. if you had a tire completely full of nitrogen it will not do this. i don't think it has anything to do with the size of the molecule.

MDchanic

A HA!

The Ideal Gas Law, PV = nRT, where
P is the pressure
V is the volume
n is the number of moles (a measure of the number of actual molecules)
R is a constant (0.0821), -and-
T is the temperature,

applies to all gasses, without exception.

Therefore, if we keep the volume (the amount of space inside the tire) and the number of moles (the actual, uncountable, number of gas molecules present inside the tire) constant (same tire, same amount of gas), and we vary the temperature, what has to happen in order for the two sides of the equation to remain equal?
Right, if the temperature goes up, the pressure has to go up, and if the temperature goes down, the pressure has to go down.
Nitrogen is not endowed by the Creator with any special privilege that exempts it from this law, as much as lying thieves in tire stores may want you to believe that it does.

[interestingly, the converse applies as well, ie: when the pressure goes up, the temperature has to go up as well, which is why air compressors get hot.]

So, as I was saying, I call BS on that. And I hate thieves.

- Eric

71 Cutlass

Before I converted to 134a, I used to buy Freeze 12 for only $10 a can and that was just 3 years ago. Everything must be going up in price, b/c tonite my wife told me bacon was $8.00 a pack at the grocery store!

stevengerard

I have heard there is a new version coming out as well R134-B and yes I bet that is starting to drive up the price of 134.

I have heard AC folks say that R12 is plentiful as well as it is used in many industrial applications so if you are connected to the right person you can get it easily.

redoldsman

My 99 Expedition has a slow leak in the AC. It is too expensive to fix so I bought one of those charge hoses with the gauge on it. I mentioned it to my daughter who drives the Expedition most of the time and she said that Big Lots had 134 on sale for $8.00 a can. I went up and bought the last 11 cans they had. Beats the $15.00 at O'Reilly.

jensenracing77

I'm not smart enough to understand completely but i do know that pressure on Nitrogen does not change much at all if any just by temperature. in the 4 wheeler racing world we run nitrogen in the shock reservoirs for this reason. i can take a shock with the same ambient temperature with 300psi of nitrogen in the reservoir. then go out and race a hard MX race and get the shock so hot that it almost reaches the melting point of the seals inside. the nitrogen pressure don't change more than about 5 psi. this 5 PSI from 300PSI is the difference of the oil heating up and expanding creating more pressure on the oil side of the nitrogen bladder (or piston). these don't have more than about 10 cubic inches of nitrogen so the pressure would be amplified by such a small space with higher pressure. if we ran regular air from an air compressor that high then went out to race the reservoir would likely explode. i do agree that what the tire shops claim is BS because the tire has regular air in it before the add the nitrogen. it is maybe 1/2 nitro and 1/2 air.

MDchanic

I would strongly recommend checking your assumption experimentally:

Fill four identical tires to the same pressure while at the same temperature, two with nitrogen, two with oxygen.

Place one with nitrogen and one with oxygen in one temperature environment for enough time that its temperature stabilizes, and the other two in a different environment (in the wintertime, you could put two outside at 10°F and two indoors at 60°F overnight).

Check all the pressures.

As far as the behavior of nitrogen in shock absorbers, its temperature change with use may be more predictable because it contains no water vapor, which may behave differently when cold, if it has condensed as liquid water, than it does when hot, if the water has evaporated and now contributes its partial pressure to the total gas pressure. Perhaps someone familiar with shock absorber design can contribute a word here - all I can tell you is that the laws of physics do not bend like the laws of Man.

- Eric

OLDSRALLYE350

This article pretty much sums up what i aready assumed about the nitrogen in tires. http://www.tirerack.com/tires/tirete...=191&index.jsp=&

Lady72nRob71

Personally, I call shenanigans on nitrogen in tires.
Whether air or nitrogen, we are still responsible for checking the pressures, as wheels and tires leak - although very slowly. Rubber is not totally non-porous. None of my tires can go a whole year and not need something. And if I do not have a nitrogen source at home, I would have to add air anyway, defeating the purpose of the low-temperature expansion.
Just like "HD", it is simply a part of the marketing world Bingo game.........